The ultimate objective of the research projects in this application is to identify and understand the components of immunoincompetence so as to rebuild immunity, thereby extending and enhancing survival. It is anticipated that the murine projects will inform the clinical studies, and that clinical insights will feed back to the animal and laboratory projects for further assessment. Project results will be conveyed to other members of the program with the assistance of members of the Biostatistics Core. Members of the Biostatistics Core will assist all the research projects contained in this program. The purpose of the Biostatistics Core, Core D, is to provide biostatistical support to all the research projects and cores included in this Program Project. The aims of this Core include: 1. To provide biostatistical collaboration for clinical research protocols. This includes all aspects of the design, conduct, analysis, and reporting of the clinical studies of prospective therapeutic interventions, as developed from the scientific studies of Projects 4, 5, 6, and 7 and implemented in the Clinical Core, Core B, and through the Immune Assessment Core, Core C. 2. To provide biostatistical collaboration for the murine studies, including all aspects of the design and analysis of such studies, as presented in Projects 1, 2, 3, 4, 5, and 7. 3. To provide biostatistical collaboration for the laboratory studies. This includes all aspects of the design, conduct, analysis, and reporting of such studies, as well as the analysis of laboratory results obtained in conjunction with, or as outcomes in the human and murine studies of the components of the Program Project. 4. To provide a central biostatistical resource for the design, analysis, and reporting of murine and human microarray studies, in conjunction the local biostatistical collaborators already in place, in Projects 1, 2, and 3. 5. To collaborate with the designers of the web-access database, to assure that appropriate data are collected and that those data are readily downloadable for analysis. 6. To assist, in conjunction with the Clinical Core, in the oversight and quality assurance of data obtained in the clinical studies, including the identification of fields to be computerized. 7. To assist, in conjunction with the Immune Assessment Core, in the oversight and quality assurance of laboratory data obtained in the clinical studies.